You may be tempted to head out for a run without first eating something, thinking you’ll increase the amount of fat you burn. But if you don’t nourish your body properly before engaging in strenuous physical activity, you may burn more than just fat.

One of the biggest issues of “running on empty” is that you risk burning muscle for fuel if you don’t have enough readily available fuel to draw from. When you exercise intensely on an empty stomach, your body doesn’t have enough glucose or glycogen stores and may instead turn to lean muscle mass to keep you going.

Another issue you may encounter if you don’t nourish your body before you run is being unable to get in your full workout or perform up to expectations. You may find yourself feeling tired or lightheaded, or may notice your performance suffers since you’re not running at full efficiency.

When you’re running for a long time, such as when training for or participating in a marathon, and you don’t fuel your body appropriately throughout your run, your body may run out of glucose and glycogen stores. You’ll essentially be “running on empty” even if you fueled properly prior to the start of your run. This can impact your performance or may cause you to end your run prematurely.

So how do you avoid running on empty? Here are some tips to keep in mind:

Time your food consumption. You don’t want to eat a huge meal and then lace up your sneakers for a run. But you don’t want to go hours without food either. A good rule of thumb is to wait 3-4 hours after a large meal before running. Eat smaller meals 2-3 hours before you’re ready to exercise. To make sure you have enough energy to keep you going, have a small snack about an hour before you hit the pavement.

Pay attention to what you eat. Opt for a snack or meal that contains healthy carbs, protein and a little bit of fat. Limit the amount of fat and fiber you consume pre-workout so your body isn’t using too much energy for digestion. Some good choices are a banana with nut butter or some yogurt topped with granola. A good rule of thumb is to aim for about 15 grams of carbs if you’re running for less than an hour or closer to 30 grams of carbs if you’re heading out for longer than that. Ultimately, you’ll have to see what types of food and how much of it works best for you.

Consider your training intensity. If you’re just going out for an easy, short run, you don’t need to worry too much about what you eat. Just make sure you’ve eaten something small before heading out. But if you’re planning a longer run (an hour or more) or are training at a high intensity, what and how much you eat becomes more important.

Don’t forget to hydrate. In addition to food, your body also needs to be well hydrated. Drink water or other fluids before, during and after your run but don’t overdo it, just drink according to your thirst. Water is adequate, but if temperatures are warm or you have been running for a long time (such as during a marathon), a sports drink is a good idea because it helps replenish electrolytes and will also provide you with additional carbohydrates to use as an energy source.

Sources:

http://www.livestrong.com/article/501975-what-happens-if-i-workout-without-eating/

http://running.competitor.com/2014/06/nutrition/running-101-hydration-during-running_7800

http://running.competitor.com/2013/11/nutrition/the-new-rules-of-marathon-nutrition_67841

http://health.usnews.com/health-news/blogs/eat-run/2013/09/05/what-to-eat-before-running